The present invention relates to a automated positioning apparatus in a machine such as multiple heads woodworking apparatus including a plurality of relatively fixed work operating tools and particularly to positioning apparatus for positioning of the tools for operating on the work member.
In automated woodworking machines for forming and shaping the contour and configuration of a wood member, a substantial plurality of woodworking tools are mounted in predetermined positioning in spaced relation to a work conveying unit. Each of the many tools is accurately positioned for working on the wood member as it passes the tool station. The work is carried by an appropriate transport or conveyor unit sequentially past the tools. In various applications, in excess of 50 different tool axii at the work stations are provided for properly locating the individual tools and thereby creating defined shaping and forming of the various surfaces and edges of the wood product during a single cycle through the machine. Various tools are inventoried and mounted at each station in order to produce various profiles. Thus, cabinetry panels, doors, windows and the like are typical elements which are processed through relatively high speed woodworking and shaping machines. Such machines are relatively high production machines. The prior art machines use precision motors interconnected through precision lead screws positioning devices and the like for accurately setting of the tool in a preset operating position or in position to move relative to the work. The tool may in special instances have some limited movement with respect to the work as the work moves past the station, but generally the tools are held in a fixed position relative to the moving work. Generally, such machines are expensive complex machines in order to provide a long life and reliable operation. Each head is individually preset in the particular required position for the particular design and work of the wood product required. Accurate positioning of all the tools is a significant aspect of the machine design. Individual manual setting of the various cutting tool may require an excess of 30 to 40 minutes set up time. Further, the individual adjustment is operator dependent and may therefore result in some waste or waste product as the result of human error. U.S. Pat. No. 3,814,153 which issued June 4, 1974 discloses a special woodworking apparatus in which a succession of work pieces are transported by a conveyor unit past a plurality of preset woodworking stations and tools. As more fully disclosed therein, the various working tools illustrated are positioned to a particular pattern to provide a path related to a predetermined shaping of the edges of the woodwork pieces as it travels longitudinally past the tools. Other tools are shown for other shaping of the workpiece, or otherwise changing the workpiece as by cutting, providing appropriate recesses and openings through boring and routing tools. Each of the tools has an appropriate electric motor, and is mounted on a carriage for proper positioning relative to the work.
U.S. Pat. No. 3,323,029 discloses a single portable positioning device specially constructed for selective coupling to each of the tools in a multiple headed machine. The tool is selectively connected for each machine tool for actuating a particular motor and then manually operates the system sequentially to adjust the tool to an exact postion. When the adjustment is complete, the adjustor unit is unplugged from the machine and moved to the next station. This however continues to use the same basic approach of a single individual control of each of the heads with a manual adjustment.
Generally, 3 to 5 axis machine tools and woodworking machines are used in production of shaped wood parts. Such machines will cost anywhere from $100,000.00 to $150,000.00 with the cost directly related to the number of different tool stations. Thus the cost of the stations and particularly the adjustment means is very significant. Further, difficulty in the accuracy of the system with present day positioning tends to vary with the age of the machine. The repeatable operation of the machine then becomes difficult and unreliable unless an expensive update of the drive systems as well as the tooling is provided.
Further, existing machines in the marketplace, which do not include the most current technology, are difficult and expensive to retrofit to the most current technology because of the use of relatively expensive drives, mountings and the like.
Although a very substantial number of woodworking machines and the like where a multitude of axii must be positioned are commercially in place as the result of the productivity of such machines, there is a continuing need and request for a woodworking type machine having a simplier and particularly less costly position control system to permit the more rapid and effective set up of the machine for establishing a given sequence of operation of the sequential tooling.
An absolute positioning control system with a computer based controller is disclosed in an article entitled "Computer Driven Tenoner is User Friendly" published in the January 1987 issue of "Furniture and Manufacturing Management", discloses a multiple tool wood working apparatus in which each tool element is provided with an absolute positioning drive in combination with a feedback system having an absolute position measuring device which permits simplification of the control system. Each tool axis includes a separate linear measuring device having one component fixed to the moving head and the other part fixed to the machine support structure to obtain an absolute position signal. A special precision type of a lead screw and drive connection is not required because the positioning is to an absolute position and the measuring device establishes an absolute position signal of the positioning of the head. The measuring device is connected to a computer based controller having the axis information for the tools stored in a computer program for positioning of the tools.